Merge branch 'tr/notes-display'

* tr/notes-display:
  git-notes(1): add a section about the meaning of history
  notes: track whether notes_trees were changed at all
  notes: add shorthand --ref to override GIT_NOTES_REF
  commit --amend: copy notes to the new commit
  rebase: support automatic notes copying
  notes: implement helpers needed for note copying during rewrite
  notes: implement 'git notes copy --stdin'
  rebase -i: invoke post-rewrite hook
  rebase: invoke post-rewrite hook
  commit --amend: invoke post-rewrite hook
  Documentation: document post-rewrite hook
  Support showing notes from more than one notes tree
  test-lib: unset GIT_NOTES_REF to stop it from influencing tests

Conflicts:
	git-am.sh
	refs.c

git-rebase.sh

@@ -79,6 +79,7 @@ continue_merge () {
 		then
 			printf "Committed: %0${prec}d " $msgnum
 		fi
+		echo "$cmt $(git rev-parse HEAD^0)" >> "$dotest/rewritten"
 	else
 		if test -z "$GIT_QUIET"
 		then
@@ -151,6 +152,11 @@ move_to_original_branch () {
 
 finish_rb_merge () {
 	move_to_original_branch
+	git notes copy --for-rewrite=rebase < "$dotest"/rewritten
+	if test -x "$GIT_DIR"/hooks/post-rewrite &&
+		test -s "$dotest"/rewritten; then
+		"$GIT_DIR"/hooks/post-rewrite rebase < "$dotest"/rewritten
+	fi
 	rm -r "$dotest"
 	say All done.
 }